The Modulation Transfer Function Measurement And Optimization Method Of Electron Multiplying CCD Imaging System

The modulation transfer function(MTF)of the electron multiplying CCD(EMCCD)imaging system is a key indicator of the imaging performance of an EMCCD imaging system and the optimization of the imaging system MTF can improve the resolution of the imaging system.EMCCD imaging systems play a major role in such areas as night-time reconnaissance,biological observation,space exploration and remote sensing navigation.Therefore,measuring and optimizing the MTF of the EMCCD imaging system will affect developments of many areas.In this paper,researches of EMCCD imaging system MTF measurement and optimization methods are in the following aspects:In this paper,the working principle of the EMCCD device and the working process of the imaging system are analyzed.The influencing factors of the EMCCD imaging system MTF are analyzed.After researching influential factors of EMCCD imaging system testing methods,the testing system was set up,and the system control and data processing program were written.Optimized MTF testing system of the imaging system.All those works are to complete the measurement of EMCCD imaging system and MTF influencing factors.The MTF test system was used to analyze the influence of sampling integral,quantum efficiency,charge transfer efficiency and electron multiplication gain on the imaging system MTF of EMCCD devices.In this paper,the Hamamatsu C9100 EMCCD camera and the Andor Luca EMCCD camera were tested.The MTF of the EMCCD imaging system became smaller with the increase of the EMCCD sampling interval.According to the test results of quantum efficiency and the effect of quantum efficiency on the MTF of the EMCCD imaging system,the MTF of the imaging system will be enhanced by choosing high-quantum-efficiency EMCCD.By comparing the MTF curve of imaging system with different integration time,it is concluded that the effects of integration time on imaging system MTF can be neglected when the integration time exceeds 100ms.Both the analog gain and the electron multiplication enlargement reduce the MTF of the imaging system.The MTF of the imaging system with analog gain is better than the electron multiplier gain.Under low light condition,increase the integration time,then set the low multiple of the analog gain,and finally open the electron multiplier gain,in this way the MTF of imaging system is highest.